GOODYEAR, Ariz. -- Tony Gwynn Jr.'s lingering shoulder woes are prompting the Brewers to keep an eye on the free-agent market for outfielders.

"I would say very, very casually that we're keeping an eye out," assistant general manager Gord Ash said Friday. "Believe me, we have had a number of calls from agents of players who don't have jobs yet. They see a player goes down [with an injury] and they make a call.

"Until we have a definitive answer on Tony, I don't think there's any desire to rush into something."

John Boggs, the agent for free-agent outfielder Dave Roberts, has called the Brewers in regard to the speedy veteran. Roberts was released by the Giants on Friday despite being owed $6.5 million in 2009. The Brewers made a run for Roberts prior to the 2007 season, but sensed little mutual interest before he inked a three-year, $18 million deal with San Francisco.

Giants GM Brian Sabean told reporters that he had tried trading Roberts in recent months, but found no takers. Any team that picks Roberts up now would only owe him the $400,000 league minimum; the Giants would be on the hook for the rest.

Other left-handed-hitting outfielders on the market include Jim Edmonds -- the Brewers have not heard from his rep, Ash said -- and Luis Gonzalez.

"Part of the issue is that guys like that don't necessarily want to play part-time," Ash said. "If you're looking at [Ryan] Braun, [Corey] Hart and [Mike] Cameron, whoever wants to come with us is going to have to accept the fact that they are going to sit on the bench. Some players aren't ready to do that."

Braun, Hart and Cameron are Milwaukee's projected starters in left field, right field and center, respectively. Gwynn is the only other outfielder on the 40-man roster, and the Brewers opened camp with non-roster invitees Chris Duffy and Trot Nixon in the fold as well. This week, the team added Lorenzo Cain, but he will almost certainly begin the year in the Minors.

The Brewers also are looking at Brad Nelson, who has played some outfield in the Minor Leagues, but last season moved primarily back to first base. Nelson has impressed manager Ken Macha to the point he's being strongly considered for a reserve outfield job.

Gwynn has appeared in Cactus League play as a designated hitter, but he's been unable to throw because of lingering soreness in his right shoulder. He underwent an MRI over the weekend that showed some inflammation, and he received a cortisone injection.

Gwynn used the down time to depart camp and return home to San Diego, where his wife is due to give birth to the couple's second child. He is scheduled to return on Sunday night and will see a doctor on Monday.